When I was installing my lift blocks the other day, I saw oil around my rear differential. Looks like something is leaking. My truck has about 30k miles. I installed the lift blocks and was wondering if that would void my warranty?? Or should I remove the lift blocks than take it in? Please help!

So I took my truck, got a call back and they asked me if I had someone work on the truck because all the bolts are loose. Obviously no one has worked on my truck. So I asked if they had little kids working at their plants tightening the bolts! Lol